Seatbelt assemblies and systems are in widespread use in motor vehicles. Present systems have certain common elements including seatbelt webbing which extends across the upper and lower torso of the occupant, and a retractor for allowing protraction and retraction of the webbing so that the belt may adapt to different sizes of occupants and be conveniently out of the way when not being used. Seatbelt assemblies further typically include a buckle which releasably attaches to a latch plate.
Seatbelt assemblies must be securely affixed to motor vehicle structural elements in order to provide the necessary restraint effect in vehicle impact conditions and further to meet government regulations. Further, seatbelt assemblies must securely retain an occupant within its seat, while also allowing the occupant easy ingress and egress from the seat under a variety of conditions and situations.
Typical seatbelt assemblies include a buckle that is securely mounted to a vehicle structure, such as a seat frame or the floor of the occupant compartment. The buckle typically includes a slot that is sized to receive and retain a latch plate.
The latch plate is typically attached to the seatbelt webbing. The seatbelt webbing is typically fixed to the vehicle structure at one end, and the opposite end is typically fixed to a retractor having an internal spool that is configured to protract and retract the webbing in response to various loads. The latch plate is typically attached by passing the seatbelt webbing through an elongate opening or slot, such that the latch plate can slide along the webbing and be adjusted relative to the size of the occupant. The latch plate is typically attached to webbing such that the latch plate remains on the webbing, whether the seatbelt is in the buckled or unbuckled configuration.
The buckle is typically in the form of a housing that includes a pushbutton. A single slot is provided at the top of the buckle and defined between the pushbutton and the housing, into which a single latch plate is inserted. In other forms, the pushbutton is provided on the side of the housing, and the housing defines the slot at the top of the buckle.
Because the seatbelt is inherently inserted and removed multiple times through the course of its life, there are prolonged instances where the seatbelt is in an unbuckled condition. In this condition, the slot at the top of the housing is open and capable of receiving the latch plate when buckling is desired by the occupant.
In some approaches, the buckle is maintained in an upright position to provide easier access to the occupant. In other approaches, the buckle may lay flat against the vehicle seat. Often, the buckle is recessed in a vehicle seat to provide a low profile vehicle seat.
In each of these approaches, the slot is susceptible to debris or other objects being inserted into slot or inadvertently falling into the slot. Such debris can include coins, pins, paperclips, gravel, hairpins, rubber bands, or other similar items. Debris becoming lodged within the buckle can interfere with proper buckle operation.
Seatbelt buckles have been developed with smaller slots, but the smaller slot results in a smaller latch that may not meet design criteria. For example, a traditional belt buckle slot has a width extending across the buckle and a height that corresponds to the thickness of the latch plate. The slot also has a depth for receiving at least a portion of the length of the latch plate.
One example of a smaller slot design has been used with child seats that use a pair of separate latch plates in a five point seatbelt design. The smaller slot has a smaller width, while having approximately the same height. These designs require one latch plate to be buckled from one side of the child occupant and a second latch plate to be buckled from the other side. Accordingly, two slots are used, with each slot having a smaller width than a traditional buckle. The latch plates meet at a central buckle that is disposed between the legs of the child occupant. However, such designs are impractical for occupants that have outgrown a child seat. They are more uncomfortable and are difficult to adjust to accommodate occupants of varying sizes. Moreover, the use of two separate latch plates necessarily makes buckling and unbuckling more difficult than a single latch plate and buckle system.
Accordingly, improvements can be made to seatbelt buckling systems that improve on a buckle's resistance to debris.